OT. Flail mower interlock wiring

Post back when you have that information. Can't do a circuit if we don't know how the state of the key components. I have a sneaky feeling it's not as simple a problem as it first appears.

Hello Dave

First reply from Robin re. switches. (I have asked him to confirm the operation):

"They are push to make switches. NC when clutch engaged or gear engaged, NO when not engaged or no gear selected. At least I'm pretty sure that's the case. I did wire them up originally much as you'd first think of wiring them up, only to have the engine die when you engaged *both* clutch and gears."

Indeed, a TT is required. I was trying to work it out 'in my head' as a means of encouraging sleep last night and agree that it is not obvious - certainly not to me.

Will come back with the switch detail.

Richard

More:

It's a 1970s or more likely early 80s Saxon pedestrian flail mower with a Robin EY40B pull start engine fitted with the separate coil and KTR unit. Both the switches are push to make, the clutch switch makes on clutch engagement, the gearbox switch makes on reverse gear selection only. As far as I can work out, they were originally wired in series as that's what the cable remnants seem to determine.

Richard

I didn't bother thinking about it later but what makes it tricky is that:

Clutch in or out, gear in or out are all valid "engine run" states so if any of those 4 states kills the engine it doesn't work. I can't help thinking that there must be another (centrifugal?) switch that indicates that the engine is running and but that would need a "start" override...

Indeed. An interesting conundrum.

Richard

From my reading of the thread and a little thought I suspect the interlock may only be designed to kill the engine *if both* the clutch is engaged (and said clutch is flail drive clutch, not wheel drive clutch) *and* reverse gear is engaged at the same time in which case a simple series connection of the switched in parallel with the engine kill switch should suffice.

Reply from Robin:

That would be a logical assumption and quite possibly the answer, but the layout of the belts and clutch levers doesn't lend itself to this being the logical layout: There are two hand levers for the two clutches (calling it a clutch is glorifying it, it's just a belt tensioner arrangement), one for the gearbox drive, and one for the flail drive. The clutch lever on the left handlebar is set up to operate the left belt / clutch arrangement which operates the gearbox drive, and the clutch lever on the right handlebar is set up to operate the right belt / clutch arrangement which operates the flail drive. A simple swapping of the lever control cables will give the 'no reverse with flails engaged' scenario detailed below - and as I said above, quite possible the answer - but the controls / cables / belts layout doesn't lend itself to this and would explain why the previous owner(s) had installed it this way.

Of the two clutch levers, only one has the cut out switch facility.

Many thanks for the AFL bod who came up with this probable solution. When back at work on Monday I will see if the cables will fit the other way around.

cheers,

Robin

In article , Richard Savage writes

Is it electric start, or rope?

In article , Richard Savage writes

I'm late to the party, obviously, but they seem like they were intended to be cutout switches (preventing a dangerous operation) rather than start-enable switches, so they won't prevent starting with one or other engaged, but will kill the motor if you attempt to remove your toes with the machine.

I'd guess they were wired out by a mower shop at some point in the past, possibly because they were unreliable (that arrangement isn't failsafe, and it might be better to not rely on it).

In particular, since the clutch is slipping-belt, is it possible the lever alignment isn't guaranteed? Could it run without activating the microswitch?

Also, are the microswitches good enough to work reliably, or might they clog or jam?

I wonder if starting from scratch might be best.

S.

PS: Ignore my earlier message - I was traversing the other fork of this thread and you've answered my question about starting.

Hi Simon

Robin appears to still be alive, judging from his email traffic, but hasn't confirmed whether his cable re-routing has worked. I do know, however, that he is in the process of ordering some Bowden cables.

Richard

In article , Richard Savage writes

That's a relief.

I had visions of a large blood puddle in the middle of a half-trimmed rough pasture, and a severed arm, still gripping a phone, with a dying battery but still bleeping, and flashing "you have mail..."

I may just have been watching too many of those "Inspector Waxwork" mysteries the wife likes, though.

S.

ROFL or perhaps FAOFL (Flail Around On Floor Laughing)

Richard :-)